<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>后盾人</title>
    <style>
        h2 {
            position: relative;
            cursor: pointer;
        }

        h2:hover::before {
            content: attr(data-title);
            color: green;
            position: absolute;
            background: #555;
            color: #fff;
            left: 10px;
            bottom: -30px;
            padding: 5px;
            border: solid 1px #333;

        }
    </style>
</head>

<body>
    <h2 data-title="houdunren.com">后盾人</h2>
</body>

</html>